1. Field of the Invention
The present invention relates to an instrument for measuring a refractive power of an examined eye.
2. Related Art
An instrument for measuring an eye refractive power has been widely used in medical facilities such as an ophthalmological clinic. Examples for such an instrument employ retinoscopy, which are described in Japanese Unexamined Patent Application Publication No. H7-213485 and No. H8-164114.
However, these examples have drawbacks related to a decrease in reliability of data measured for an astigmatic axis (axial angle of astigmatism), which may occur when the instrument is placed with a rotational bias relative to an examined eye. Particularly, when an instrument of a handheld type is used, the reliability of an astigmatic axis tends to be degraded due to handshaking of an operator.